[PATCH] btrfs: remove unused btrfs_root::defrag_trans_start

[David Sterba <dsterba@suse.com>]

Last touched in 2013 by commit de78b51a2852 ("btrfs: remove cache only
arguments from defrag path") that was the only code that used the value.
Now it's only set but never used for anything, so we can remove it.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/ctree.h       | 1 -
 fs/btrfs/disk-io.c     | 4 ----
 fs/btrfs/tree-defrag.c | 5 ++---
 3 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d8301bf240e0..297c51d3c74b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1075,7 +1075,6 @@ struct btrfs_root {
 
 	u64 highest_objectid;
 
-	u64 defrag_trans_start;
 	struct btrfs_key defrag_progress;
 	struct btrfs_key defrag_max;
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c70d47b8090a..3aa3ae99710e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1141,10 +1141,6 @@ static void __setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
 	memset(&root->root_key, 0, sizeof(root->root_key));
 	memset(&root->root_item, 0, sizeof(root->root_item));
 	memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
-	if (!dummy)
-		root->defrag_trans_start = fs_info->generation;
-	else
-		root->defrag_trans_start = 0;
 	root->root_key.objectid = objectid;
 	root->anon_dev = 0;
 
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index 16c3a6d2586d..d3f28b8f4ff9 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -133,10 +133,9 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
 		ret = 0;
 	}
 done:
-	if (ret != -EAGAIN) {
+	if (ret != -EAGAIN)
 		memset(&root->defrag_progress, 0,
 		       sizeof(root->defrag_progress));
-		root->defrag_trans_start = trans->transid;
-	}
+
 	return ret;
 }
-- 
2.25.0